Supporting base for chimneys



Jun 1, 1965 w. s. NEWBILL, SR

I SUPPORTING BASE FOR CHIMNEYS Filed May 1, 1962 INV EN 1 OR WILLIAM S. NE WB/LL 9?.

United States Patent 3,186,330 SUPPORTING BASE FOR CHIMNEYS William S. Newhill, Sr., 2227 County St., Portsmouth, Va. Filed May 1, 1962, Ser. No. 191,492 7 Claims. (Cl. 93-46) This invention relates to chimneys, and more particularly to prefabricated chimneys made of sheet metal of the type disclosed and claimed in my prior application Serial No. 762,448, filed September 22, 1958; now Patent No. 2,976,797 granted March 28, 196 1.

Chimneys of this type usually comprise a flue formed from one or more tubular sheet metal conduits connected between a device within .a building and the exterior of the building, usually extending above the roof thereof.

Along the length of the run of flue conduit, which is in proximity to the structure of the building, it is surrounded by one or more tubular conduits spaced from the central flue and from each other to provide concentrh cally arranged tubular passages for insulating air. This air may enter at the upper end of one of the surrounding conduits, pass down between the spaced conduits, and return upwardly to the atmosphere between the flue and another conduit. It is also possible to arrange for cool insulating air to enter one or more surrounding conduits at their lower ends to be expelled at their upper ends to the atmosphere exterior of the building, or to construct systems which include both systems.

In the general type of chimney disclosed in my prior patent, means such as a supporting base is provided to support the lower end of the flue and the surrounding air conduits. As shown in this patent, the supporting base is fabricated of sheet metal and a portion of this metal, which is in direct contact with substantially the entire periphery of the flue, is also in contact with the building structure.

In consequence, this arrangement has been considered disadvantageous dueto the possiblity that if the building is of combustible construction, such as a wood frame building, there exists the possibility of an excessive heat transfer between the flue and the Wooden supports.

Therefore, one object of the present invention is to provide a supporting structure for sheet metal chimneys of the air-insulating type wherein the amount of conductive heat transfer between the flue and the supporting structure is reduced to a minimum.

It is another object of the invention to provide a supporting base structure of simplified construction for sheet metal chimneys.

Other objects and advantages will be evident to those skilled in the art after reading the following specification in connection with the annexed drawing, in which:

FIG. 1 is a cross sectional elevation of a preferred form of chimney base in accordance with the present invention;

FIG. 2 is a plan view of the same; and,

FIG. 3 is a perspective view of the same.

Referring now to the drawing in detail, the numeral indicates a generally rectangular base plate, preferably constructed of sheet metal; while the numeral 11 indicates generally a tubular vertically extending shroud. The lower portion 12 of the shroud is rectangular incross-section to be disposed in abutting relationship to the margins of the base plate 10, while the upper extremity 13 of the shroud is of tubular cross-section. The lower extremity of the shroud is provided with extending marginal flanges 14 and the dimensions of the base are such as to provide marginal flanges 15, which are turned upwardly and backwardly over the flanges of the shroud and forced downwardly in contact therewith.

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The entire structure is supported by suitable sheet metal straps, indicated generally by numeral 16. These straps are preferably placed one at the mid-point of each side of the base, and the lower end 17 of each strap is inserted between the marginal flanges 14 and 15 prior to their final assembly and secured permanently as by means of a rivet \18. The upper end 19 of each strap may be bent over the top of a supporting portion of the building struc. ture, such as the floor joist 2t), and secured thereto as by means of a nail 21.

The flue proper (not shown) consists of a number of tubular sheet metal conduits connected with the tubular section indicated by numeral 22, and interconnected with each other in a well known manner according to the height of the building. The section 22 projects vertically through an opening 23 cut in the center of the base plate 10. This opening is somewhat larger than the outside diameter of the flue conduit so that there will be no metal to metal contact, and also to permit the entrance from below a portion of air from the interior of the building to assist in forming an insulating blanket around the flue An annular ring 24 is supported in position concentrically with respect to the opening 23 by means of .a number of brackets, indicated generally by numeral 25; The ring has an inside diameter slightly larger than the outside diameter of the flue section 22, so that this section may slidably engage with the ring. Each of the brackets 25 may be fabricated fro-n1 a strip of sheet metal shaped to form a lower medial portion 26 having an inner upstanding leg portion 27 and an outer upstanding leg portion 28. The medial portion of the bracket extends horizontally and is attached to the base plate by means of the rivet 29, while the ring 24 is supported by connection with the upper ends of the inner legs as by means of the rivets 30.

As previously stated, the flue section 22 is slidable within the ring 24, but in order to provide support for the string of tubular sections comprising the flue in its entirety, the section 22 is provided with an outwardly projecting portion which rests on the ring to prevent downward movement of the flue beyond that point. This projection preferably takes the form of an annular bead 31 integrally formed by outwardly swaging the metal of the tubular conduit.

An intermediate conduit 33 may surround the flue and is spaced outwardly therefrom. The lower margin 34 of this intermediate conduit is supported and spaced above the base plate 10 by rivet 32 joined with the outer upstanding leg 28 of the bracket. The lowermost section 35 of the outer air-insulating conduit is coupled in the usual way with the circular upper extremity 13 of the shroud.

It will thus be observed that the chimney-supporting structure, when installed, will furnish a base upon which the various air-conducting conduits may be installed, as well as the flue conduit. The latter is assembled by inserting the flue conduit into the supporting ring from above and allowing it to slide downwardly until the protruding annular bead rests upon the ring.

Further, it will be observed that a certain proportion of insulating air may enter the system through the annular opening in the base plate surrounding the flue, the remainder entering at the upper end between the outer and intermediate conduits and flowing downwardly until it passes into the space between the flue and the intermediate conduit for travel in an upward direction to the atmosphere. Or, all of the insulating air may enter through the annular opening for upward travel through both annular passages.

Having described the invention in detail, it will be obvious that various modifications and improvements may be made by those skilled in the art which would come within the scope of the attached claims.

I claim:

1. In supporting base structures for prefabricated sheet metal chimneys, a horizontal sheet metal base plate having a central opening,'means to attach the :base plate to a building structure, three sections of sheet metal tubing of progressively greater diameter vertically disposed concentrically with respect to said central opening, said opening being substantially greater than the exterior dimension of the innermost of said metal tubes, means to support said innermost tube in fixed position projecting above and below said base plate, means to support said next larger tube concentrically spaced from the innermost tube and with its lower margin spaced above the base plate, and means to support the outermost tube concentrically spaced from the next larger tube, said last mentioned means including means to circumferentially join said outermost tube with the base plate to form an enclosure for circulating insulating air, whereby the space between the innermost tube and the next larger tube and the space between the next larger tube and the outermost tube will be in communication with each other at their lower ends, and both said spaces will be in communication with the exterior atmosphere through the opening in the base plate, said opening in the base plate being smaller than the cross-section of the intermediate tube, said means to support said innermost tube including an annular horizontally disposed member within which the innermost tube is slidably received, means to attach the annular member to the base plate, and means integrally formed with the innermost tube to limit vertical movement thereof with respect to said annular member.

2. The invention as defined in claim 1, wherein said innermost tube is formed of sheet metal and means to limit vertical movement thereof comprises an integrally formed exteriorly projecting annular bead to axially abut against said annularly disposed member.

3. In supporting structures for prefabricated sheet metal chimneys, the combination including a generally box-like enclosure having a first opening extending in a horizontal plane at the bottom and a second opening of larger crossseotion at the top in vertical alignment with the first opening and extending in a horizontal plane, a ring-shapedmember adapted to slidingly receive a length of sheet metal flue pipe of somewhat smaller crosssection than the cross-section of said first opening, means to sup-port the ring-shaped member in vertical alignment with the first opening and in a horizontal plane spaced from the plane of the base plate, said second opening being adapted for coupling engagement with a first length of upwardly extending sheet metal air-conducting pipe, means to vertically position said length of flue pipe within said ringshaped member, supporting means within the enclosure to position a second length of upwardly extending sheet metal air-conducting pipe Within said first air-conducting pipe and surrounding said flue pipe, said second air-conducting pipe having a cross-section larger than the cross-section of the first opening and having its lower margin spaced above the plane of said first opening, and means to attach the enclosure to a building structure.

4. The invention as defined in claim 3, wherein said box like enclosure comprises a horizontally disposed piece of sheet metal, and a generally vertically extending hollow shroud formed of sheet metal, the lower margin of the shroud terminating in a horizontal plane and being joined with said first-mentioned piece of sheet metal, the upper margin of the shroud being formed to provide said second opening, said first opening being provided in said firstmentionecl piece of sheet metal.

5. The invention as defined in claim 3, wherein said means to support said rin-g-shapedmernber and said second air-conducting pipe comprises a plurality of gene-rally 'U-shaped inverted brackets, the brackets being attached to the base at their mid portions and secured to the pipes at their terminal portions.

6. The invention as defined in claim 3, wherein said means to vertically position said flue pipe comprises an outwardly projecting protuberance integrally formed in the pipe.

7. The invention as defined in claim 6, wherein said protuberance comprises an annularly extending bead.

Rei'erences Cited by the Examiner UNITED STATES PATENTS 2,538,397 V 9/44 Howie- V98'46 2,713,301 7/55 McKann 98-46 2,976,797 3/61 Newbill 98-46X ROBERT A. OLEARY, Primary Examiner.

EDWARD J. MICHAEL, Examiner, 

1. IN SUPPORTING BASE STRUCTURES FOR PREFABRICATED SHEET METAL CHIMNEYS, A HORIZONTAL SHEET METAL BASE PLATE HAVING A CHIMNEYS, A HORIZONTAL SHEET METAL BASE PLATE TO A BUILDING STRUCTURE, THREE SECTIONS OF SHEET METAL TUBING OF PROGRESSIVELY GREATER DIAMETER VERTICALLY DISPOSED CONCENTRICALLY WITH RESPECT TO SAID CENTRAL OPENING, SAID OPENING BEING SUBSTANTIALLY GREATER THAN THE EXTERIOR DIMENSION OF THE INNERMOST OF SAID METAL TUBES, MEANS TO SUPPORT SAID INNERMOST TUBE IN FIXED POSITION PROJECTING ABOVE AND BELOW SAID BASE PLATE, MEANS TO SUPPORT SAID NEXT LARGE TUBE CONCENTRICALLY SPACED FROM THE INNERMOST TUBE AND WITH ITS LOWER MARGIN SPACED ABOVE THE BASE PLATE, AND MEANS TO SUPPORT THE OUTERMOST TUBE CONCENTRICALLY SPACED FROM THE NEXT LARGE TUBE, SAID LAST MENTIONED MEANS INCLUDING MEANS TO CIRCUMFERENTIALLY JOIN SAID OUTERMOST TUBE WITH THE BASE PLATE TO FORM AND ENCLOSURE FOR CIRCULATING INSULATING AIR, WHEREBY THE SPACE BETWEEN THE INERMOST TUBE AND THE NEXT LARGE TUBE AND THE SPACE BETWEEN THE NEXT LARGE TUBE AND THE OUTERMOST TUBE WILL BE IN COMMUNICATION WITH EACH OTHER AT THEIR LOWER ENDS, AND BOTH SAID SPACES WILL BE IN COMMUNICATION WITH THE EXTERIOR ATMOSPHERE THROUGH THE OPENING IN THE BASE PLATE SAID OPENING IN THE BASE PLATE BEING SMALLER THAN THE CROSS-SECTION- OF THE INTERMEDIATE TUBE, SAID MEANS TO SUPPORT SAID INNERMOST TUBE INCLUDING AN ANNULAR HORIZONTALLY DISPOSED MEMBER WITHIN WHICH THE INNERMOST TUBE IS SLIDABLY RECEIVED, MEANS TO ATTACH THE ANNULAR MEMBER TO THE BASE PLATE, AND MEANS INTEGRALLY FORMED WITH THE INNER MOST TUBE TO LIMIT VERTICAL MOVEMENT THEREOF WITH RESPECT TO SAID ANNULAR MEMBER. 